In a trunk transmission apparatus with devices each including a plurality of packages for transmitting main signals, functions are added to each of the main-signal packages over an extended apparatus maintenance period of 10 years or more to make the apparatus responsive to any changes in user request, to new requests, and/or to the progress of technology, during that period.
In consideration of the development scale of the software installed on an upper-level supervisory system inclusive of user terminals, in a supervisory control package, and in each main-signal package, generating a new instance for the software to manage the main-signal package, during the addition of the above functions, is undesirable if the instance only differs slightly from an existing instance.
Accordingly, the functions need to be added in association with the existing instance, and the addition itself causes another problem in that software with the added functions, and software without any added functions will be operated in mixed form. For example, whereas the supervisory control package will have functional additions to respond to the main-signal packages to which the functions have been added, the apparatus will include two kinds of main-signal packages and related software in mixed form. That is to say, some main-signal packages and related software will have added functions and some will not. In such a case, there will be a risk in that the software in the supervisory control package may conduct undue monitoring or control upon the main-signal packages for which the added functions are not supported.
A method of managing data in a distributed computer system is described in Patent Document 1 (Japanese Patent Application Publication JP-06035868-A) as an example of a technique relating to resolving a mismatch due to the presence/absence of added functions between a supervisory control package and a package to be subjected to supervisory control. In the data management method of Patent Document 1, data is deleted or added by defining activity/inactivity as an attribute in the data stored into each computer, and then assigning attribute modification information, so as to achieve reliable and easy data management.